Severe Geomagnetic Storms Research Articles

A Comparative Investigation of Different Ionospheric Models to Predict the MUF Parameter During Severe Geomagnetic Storm on 17th March 2015.

The present work aimed to make a comparative investigation between three different ionospheric models: IRI-2020, ASAPS and VOACAP. The purpose of the comparative study is to investigate the compatibility of predicting the Maximum Usable Frequency parameter (MUF) over mid-latitude region during the severe geomagnetic storm on 17 March 2015. Three stations distributed in the mid-latitudes were selected for study; these are (Athens (23.50o E, 38.00o N), Jeju (124.53o E, 33.6o N) and Pt. Arguello (239.50o W, 34.80o N). The daily MUF outcomes were calculated using the tested models for the three adopted sites, for a span of five-day (the day of the event and two days preceding and following the event day). The calculated datasets were compared for each location with the observed daily MUF values. In general, the findings show that the three investigated models gave good outcomes compared to the observed values for all selected stations. The comparative investigation results of the three tested models corresponding to the observed MUF values during the storm event revealed that the IRI -2020 Model indicate a clear impact of the geomagnetic storm on the predicted MUF values during the day of event. Similarly, for ASAPS Model, the storm's impact is clear on both the day of the event and the subsequent day, in contrast, the VOACAP model showed almost no impact of the geomagnetic storm on the observed MUF values throughout the entire study period for event 17 March 2015.

Disturbances of Ionospheric Total Electron Content during Great and Severe Geomagnetic Storms above Iraq and Surrounding Areas

Several studies have been made to understand the behavior of Total Electron Content (TEC) in the topside of the ionosphere during two types of geomagnetic storms. The aim of this research is to examine the ionospheric disturbances using the TEC parameter during the great and severe geomagnetic storms that occurred during the period (28-30 October 2003). Theexamination was conducted for the region,includingIraq and surrounding areas that cover the arealatitude 27-39oN; longitude 27-54oE). TEC data were obtained fromthe Defense Meteorological Satellite Program (DMSP), to determine the type of geomagnetic storm, the Disturbance storm time (Dst) index was gathered for the selected days from the website Koyota, Japan WDC.Fromthe results,it wasfound that there was a good relationship between Dst-indexand TEC parameter values. There is a discrepancy in observations recorded about TEC values during the period of geomagnetic storms.There were significant enhancements in the values of TEC during storms; however, there was an anomaly when the storm continued for several hours during the day, there was a highly broad increase in TEC from sunrise to sunset. Moreover, when two types of storms occurred, two peaks or more appeared, and they remained for one event, or even for more than one day. Comparisons between the observed TEC and the predicted values were applied in order to check the validity of the IRI-20 ionospheric model during the storm time above the mid-latitude studiedareas;it found that there is a non-linear correlation between them withi24 hours and three days, so the model wouldneed some modification in the future to be suitable for the Iraq region during storm time.

Unexpected major geomagnetic storm caused by faint eruption of a solar trans-equatorial flux rope

Some geomagnetic storms’ solar origins are ambiguous, making them hard to predict. On March 23, 2023, a severe geomagnetic storm occurred, however, forecasts based on remote-sensing observations failed to predict it. Here, we show clear evidence that this storm originates from the eruption of a trans-equatorial, longitudinal and low-density magnetic flux rope (FR) with weaker coronal emission and no chromospheric signs. The FR’s gentle eruption results in a faint full-halo coronal mass ejection (CME), which is missed by forecasters and not included in CME catalogs. Combining magnetic field modeling and in-situ measurements, we reveal the FR’s southward axial magnetic field as the main cause of the geomagnetic storm. This CME is the stealthiest one reported causing a severe geomagnetic storm. Our study highlights that erupting trans-equatorial FRs can generate major geomagnetic storms in a stealthy way. Characteristic observational signatures of similar eruptions are proposed to help in future forecasts.

Multi-fractal Analysis of Cosmic Rays over Mid- and High-Latitude Stations During Severe Geomagnetic Storms

Multi-fractal Analysis of Cosmic Rays over Mid- and High-Latitude Stations During Severe Geomagnetic Storms

An investigation into the influence of solar flares and geomagnetic storms on the F2 layer of the ionosphere in Western Europe during March 2024

On March 23 and 24, 2024, the M-class and X-class solar storms significantly intensified. Subsequently, from March 24 to 26, the monitoring station’s Kp index notably increased, at times exceeding 8, indicating that a severe geomagnetic storm was occurring. During this period, the IGS Global Ionosphere Maps (GIMs) displayed a substantial decrease in Total Electron Content (TEC) in Western Europe due to the impact of the intense geomagnetic storms. To investigate this occurrence, data from the Lowell GIRO Data Center were utilized. The analysis revealed that a concentrated solar flare eruption on March 23, 2024, triggered geomagnetic storm events on Earth, causing significant ionospheric anomalies in Western European countries. Specifically, compared to typical levels, parameters such as foF2, m3000F2, and TEC values experienced significant reductions in Western European countries. Moreover, the hmF2 data exhibited higher values at night and lower values during the day, deviating from the expected diurnal pattern. Analysis of the Rate of TEC Index (ROTI) indicated varying effects of geomagnetic storms across different latitudes in Western Europe. Through detailed graphical analysis, this study elucidates the alterations in the ionosphere under geomagnetic storm conditions in Western Europe, shedding light on the dynamic behavior of the ionosphere during a specific timeframe.

Time‐Lagged Effects of Ionospheric Response to Severe Geomagnetic Storms on GNSS Kinematic Precise Point Positioning

AbstractThis paper investigates time‐lag effects of ionospheric response to two severe geomagnetic storms (Kp = 8) on the degradation of kinematic precise point positioning (PPP) solutions, utilizing over 5500 Global Navigation Satellite Systems (GNSS) stations distributed worldwide. Focusing on these two severe geomagnetic storms that occurred during solar cycle 24, the study employs an open‐source positioning software package, namely RTKLIB, to derive the PPP solutions. The findings reveal significant variations in time lags across different magnetic latitudes. These variations are driven by ionospheric responses to a southward interplanetary magnetic field and subsequent decreases in the SMY‐H index during the 2015 St. Patrick's Day Storm and the 2017 September 7–8 Storm. Specifically, at high latitudes, PPP degradation primarily manifests during the main phase of the storm, resulting in delays spanning from several minutes to 1–2 hr after the sudden onset of the storm. In contrast, mid‐ and low latitudes exhibit a wider range of delays extending up to tens of hours. Notably, rapid positioning degradation is observed predominantly at the magnetic local time noon and midnight sectors. The study discusses these time lag effects concerning the intensity of various ionospheric disturbances triggered by the interactions among the solar wind, magnetosphere, and ionosphere during geomagnetic storms. The insights obtained from this research have the potential to be integrated into physics‐based and machine‐learning models to enhance forecasting capabilities of space weather impacts.

Unusual Forbush Decreases and Geomagnetic Storms on 24 March, 2024 and 11 May, 2024

As the current solar cycle 25 progresses and moves towards solar maxima, solar activity is increasing and extreme space weather events are taking place. Two severe geomagnetic storms accompanied by two large Forbush decreases in galactic cosmic ray intensity were recorded in March and May, 2024. More precisely, on 24 March 2024, a G4 (according to the NOAA Space Weather Scale for Geomagnetic Storms) geomagnetic storm was registered, with the corresponding geomagnetic indices Kp and Dst equal to 8 and −130 nT, respectively. On the same day, the majority of ground-based neutron monitor stations recorded an unusual Forbush decrease. This event stands out from a typical Forbush decrease because of its high amplitude decrease phase and rapid recovery phase, i.e., 15% decrease and an extremely rapid recovery of 10% within 1.5 h, as recorded at the Oulu neutron monitor station. Furthermore, on 10–13 May 2024, an unusual G5 geomagnetic storm (geomagnetic indices Kp = 9 and Dst = −412 nT) was registered (the last G5 storm had been observed in 2003). In addition, the polar neutron monitor stations recorded a Ground Level Enhancement (GLE74) during the recovery phase of a large Forbush decrease of 15%, which started on 10 May 2024. In this study, a detailed analysis of these two severe events in regard to the accompanying solar activity, interplanetary conditions and solar energetic particle events is provided. Moreover, the results of the NKUA “GLE Alert++ system”, the NKUA/IZMIRAN “FD Precursory Signals” method and the NKUA “ap Prediction tool” concerning these events are presented.

The Study of the Association between the Solar Wind Parameter and Cosmic Ray Intensity to a Severe Geomagnetic Storm (-350 < Dst ≤ -200 nT) during Solar Cycles 24 and 25

The Study of the Association between the Solar Wind Parameter and Cosmic Ray Intensity to a Severe Geomagnetic Storm (-350 < Dst ≤ -200 nT) during Solar Cycles 24 and 25

Analysis of global ionospheric scintillation and GPS positioning interference triggered by full-halo CME-driven geomagnetic storm: A case study

Currently, the 25th solar activity peak has commenced, driving frequent geomagnetic storms and causing irregular disturbances in the global ionosphere, leading to the scintillation of Global Positioning System (GPS) signals, consequently decreasing the accuracy of GPS positioning. Analyzing the patterns of global ionospheric scintillation and changes in GPS positioning accuracy caused by geomagnetic storms is crucial to mitigate the adverse effects of GPS positioning. Current research has primarily concentrated on analyzing the effects of geomagnetic storms on ionospheric scintillation disturbances and GPS positioning interference. However, there is a notable gap in studying the holistic impact of coronal mass ejections (CMEs)-driven geomagnetic storms on GPS performance as an integrated event complex. This study investigates the conditions under which a CME drives a severe geomagnetic storm to elucidate the space weather phenomena associated with CME-driven geomagnetic storms. The ionospheric scintillation induced by the geomagnetic storm is analyzed, while we also examine the accuracy variability in kinematic precision point positioning (PPP) and its possible leading reasons. The research findings suggest that factors such as a high-speed full-halo CME, a southward interplanetary magnetic field (IMF) Bz, and high-speed solar wind contribute to the onset of this geomagnetic storm. Ionospheric scintillation and the decrease in positioning accuracy in low-latitude regions are less pronounced compared to mid- and high-latitude areas. Geomagnetic-storm-induced scintillation increases cycle slips, leading to a decrease in PPP accuracy. Even in the cases where geomagnetic storms do not induce ionospheric scintillation, positioning accuracy can still be affected by cycle slips, deterioration of the precision of the GPS measurements, data outages, and the decrease in the number of available satellites.

Forecasting solar wind disturbances and geomagnetic storms from ground-based cosmic ray measurements

This work reports on the methods developed by our group at ShICRA SB RAS to forecast negative manifestations of space weather from ground-based measurements of cosmic rays. Such manifestations are registered on the Earth in the form of decreases in galactic cosmic rays known as the Forbush effects, various types of geomagnetic and ionospheric disturbances, as well as auroras. Only the latters are directly visible to the naked eye, while the rest can only be detected with the help of various instruments. These occurrences are all caused by passage through the Earth’s orbit, such as the substantial influxes of charged particles from both solar and interplanetary sources, interplanetary shock waves, ejections of solar material and high-speed solar wind streams, all of which are attributed to the level of solar flares and coronal activity. The state of near-Earth space weather is determined by their presence. To monitor this state, we use data collected from ground-based cosmic ray stations and employ multiple methods to analyse these measurements. Additionally, we incorporate data from the Dst-index of the geomagnetic field and measurements of the interplanetary environmental parameters gathered by ACE, WIND, SOHO and DSCOVR spacecraft at the L1 libration point to confirm events. This has led to the development of techniques for predicting terrestrial effects of space weather in the short-term (1-3 days). Our findings suggest that it is feasible to predict the occurrence of severe geomagnetic storms in real-time through the utilisation of solely ground-based measurements from cosmic ray stations.

An Assessment of Solar Cycle 25 progress through observation of SRBs and associated Geomagnetic Storms

Geomagnetic storms are severe aspects of Space Weather. They originate due to solar transient emissions such as coronal mass ejections (CMEs), whose energetic materials propagate in the Interplanetary medium and are coupled with the magnetosphere system. CME driven Geomagnetic storms are often associated with solar radio bursts (SRBs), particularly type II and type IV bursts. In this study, we present the preliminary results of solar radio observations and their associated geomagnetic activity during solar cycle 25 (SC 25) from January 2020 to June 2023, focusing on the cycle’s first four intense geomagnetic storms. The study used various radio telescopes, mainly the compound astronomical low-frequency low-cost instrument for spectroscopy and transportable observatory (CALLISTO), as well as OMNI data and the World Data Center for Geomagnetism. During the study period, it was found that 23 solar radio bursts diagnosed the geomagnetic storms with Dst <-50nT from 35 reported, including three severe storms of the SC 25. The time delay between the solar radio bursts and the arrival of CMEs and/or HSS near the Earth’s magnetosphere is estimated with an average value of 79 h within the [48–120 h] range for 23 geomagnetic storms associated with solar radio bursts. Among 35 geomagnetic storms recorded, five are recurring geomagnetic storms associated with coronal high-speed streams (HSS), while CMEs cause the rest with average speeds of 750 km/s. The current SC 25 recognizes four major storms within the scope of the study. On 21 April 2023, a type II radio burst followed by a type IV burst diagnosed the first severe geomagnetic storm on 24 April 2023. The second severe storm was unusual and detected in the absence of the precursor as a solar radio burst. The SRBs of type II burst and type IV burst extending in IP medium on 1 November 2021 tracked the third major storm of the cycle while the group of type III radio bursts, type II and type IV bursts on 24 February 2023, predicted the major storm on 27 February 2023. These major geomagnetic storms are linked to CMEs that show expanding flux ropes, which are signatures of type II and moving type IV radio bursts identified. Furthermore, the detected SRBs and related major geomagnetic storms are proof of high solar and magnetic activity of the ascending phase of SC 25. The SC 25 has been characterized overall, and its current progress is being tracked using observations of SRBs and magnetic activity during its rising phase.

Impact of two severe geomagnetic storms on the ionosphere over Indian longitude sector during March-April 2023

Impact of two severe geomagnetic storms on the ionosphere over Indian longitude sector during March-April 2023

Geomagnetic Storm Effects on the LEO Proton Flux During Solar Energetic Particle Events

AbstractDuring a few solar energetic particle (SEP) events, solar protons were trapped within the geomagnetic field and reached the outer edge of the inner radiation belt. We reproduced this phenomenon by modeling the proton flux distribution at the Low‐Earth Orbit (LEO) for different geomagnetic conditions during solar particle events. We developed a three‐dimensional relativistic test particle simulation code to compute the 70–180 MeV solar proton Lorentz trajectories in low L‐shell range from 1 to 3. The Tsyganenko model (T01) generated the background static magnetic field with the IGRF (v12) model. We have selected three Dst index values: −7, −150, and −210 nT, to define quiet time, strong, and severe geomagnetic storms and to generate the corresponding inner magnetic field configurations. Our results showed that the simulated solar proton flux was more enhanced in the high‐latitude regions and more expanded toward the lower latitude range as long as the geomagnetic storm was intensified. Satellite observations and geomagnetic cutoff rigidities confirmed the numerical results. Furthermore, the LEO proton flux distribution was deformed, so the structure of the proton flux inside the South Atlantic Anomaly (SAA) became longitudinally extended as the Dst index decreased. Moreover, we have assessed the corresponding radiation environment of the LEO mission. We realized that, for a higher inclined LEO mission during an intense geomagnetic storm (Dst = −210 nT), the probability of the occurrence of the Single Event Upset (SEU) rates increased by 19% and the estimated accumulated absorbed radiation doses increased by 17% in comparison with quiet conditions.

The role of the storm-time prompt penetrating electric field on the net distribution of plasma density over the low latitude ionospheric regions

The relative role of the prompt penetration of electric fields and neutral winds in the distribution of ionospheric plasma during geomagnetic storms over the Indian ionosphere region is studied in this paper. Four geomagnetic storms with similar onset times but of varying strengths have been analyzed with the help of data from ground-based magnetometers, and the ACE, GPS, and TIMED satellites. The strength and magnitude of the prompt penetration electric field were inferred from the magnetic field variations of the horizontal component of the magnetic field (ΔH) at Tirunelveli, a dip-equatorial station, using the ground-based magnetometers. The electron density distribution over the Indian ionospheric region was quantified using GPS-derived vertical total electron content (VTEC). Signatures of prompt penetration electric field were present for all the storms considered whose main phase was during the daytime. It is noted that as the strength of the penetration electric field increases, the latitudinal extent to which the electron density gets distributed also increases. The gradient in electron density extends even up to Shimla (a mid-latitude station) during a severe geomagnetic storm. The gradient was less for moderate geomagnetic storms. Since during the geomagnetic storm, a factor that controls electron density modulation is the neutral wind, its contribution is analyzed with the help of the thermospheric O/N2 ratio, measured by the global ultraviolet imager (GUVI) instrument, onboard NASA’s TIMED satellite. The observed increase in the O/N2 ratio does not correspond with the increase in the VTEC. We surmise that during the first day of the storm, the penetrating electric field is an essential factor that controls the electron density distribution in the low-latitude region. Later the plasma density distribution is controlled mainly by the thermospheric wind.

The Ionospheric Dynamics of the African Sector Responding to a Severe Geomagnetic Storm; the Storm of 3–5 November 2021

AbstractThe sudden storm commencement (SSC) of 3 November 2021, a severe storm was detected through disturbances in magnetospheric and ring current systems at around 1942 UT. We used a daily variation of total electron content (TEC) from ground‐based GNSS stations, ionosonde parameters and modeled zonal and meridional wind velocities to study the ionospheric response over the African region by comparing storm and quiet time variations. The equatorial GNSS station of NKLG recorded initial positive storm effects around the time of SSC, of which these effects spread over the whole African region during the main phase with positive and negative storm effects during the main and recovery phases respectively. The two disturbances at the SSC and the main phase were caused by the penetrating electric field and traveling atmospheric disturbances respectively. The analysis of TIMED Global UltraViolet Imager images revealed storm time‐induced changes in thermospheric composition during the main phase which resulted in a differential ionospheric response with intense, moderate, and weak positive storm effects in northern, equatorial, and southern regions respectively. The horizontal magnetic field components show two signatures of prompt penetration electric field that suppressed the formation of the equatorial anomaly at SSC and enhanced positive storm effects in the equatorial region at the main phase, Therefore, the ionospheric response was due to the relative contributions of prompt penetration electric field effects and equatorward traveling disturbances which depended on storm onset time, past ionospheric state, and storm phase.

Ionospheric and magnetic signatures of extreme space weather events of 17 March and 23 June 2015 over the African sector

We have investigated responses of the African sector of the ionosphere to 17 March and 23 June 2015 severe geomagnetic storms. The vertical total electron content (TEC) measurements from Global Navigation Satellite System (GNSS) stations, which are located across the African continent, have been used to estimate the deviation of TEC (ΔTEC). The observed ionospheric response to these events was different at different locations. In the main phase of the 17 march 2015 storm, a significant positive ionospheric storm (ΔTEC maximum) occurred at Meli (245.8% enhancement) and Adis (105% enhancement) stations in the post-sunset period. On the other hand, during midnight negative ionospheric storms (ΔTEC minimum: ∼ 46%–68% depletion ) were observed at Dakr, Nklg, Wind, and Haro stations. The effects of 23 June 2015 storm are more pronounced during the initial phase. In the recovery phase of 23 June storm, negative storm effects observed at the eastern dip latitude and western equatorial stations. In contrast, at the northern and southern mid-latitude stations, we observed positive storm effect during the night periods. Night time TEC enhancement at mid-latitude stations probably caused by the vertical drift of the ionospheric plasma. We have also studied the magnetic signatures of the severe storms of 17 March and 23 June 2015 by analyzing their impacts on the horizontal (H-component) of the Earth’s magnetic field. By using a moving average filter, we have separated the effect of the magnetic disturbance (DP2) and the disturbance dynamo (Ddyn). The H-component analysis shows that there was maximum oscillation of DP2 and Ddyn currents occurrence when the IMF-Bz directed southward. In the main and recovery phases of the storm, this strong current oscillation is the driver for the development of positive ionospheric effect.

2015 Yılında Meydana Gelen Üç Şiddetli Jeomanyetik Fırtına Süresince Deneysel İyonosferik Modellerin Karşılaştırılması

The geomagnetic field acts as both the shield and the electron density regulator for the ionosphere. The effect of the geomagnetic field on the ionosphere can be examined separately for the geomagnetically quiet and disturbed days. In the current study, the performance of the ionospheric models was evaluated for three different severe geomagnetic storms periods during the year of 2015, which was in the beginning of the descending phase of the 24th solar cycle. These three storms occurred during 17-18 March, 22-23 June and 20-21 December of year 2015 in which first one expressed as St. Patrick's Day geomagnetic storm. The relationship between Total Electron Content (TEC) was measured by Global Positioning System (GPS) and evaluated with NeQuick 2, IRI 2016, IRI Plas (without any input- “IRI Plas”) and IRI Plas TEC (with TEC input- “IRI Plas TEC”) global models at three Turkey IGS station namely Ankara (39.57 N, 32.53 E), Istanbul (40.58 N, 29.05 E) and Erzurum (40.39 N, 40.42 E) investigated. The comparison was made separately for pre-storm, during storm and post-storm by using the Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) metrics and symmetric Kullback-Leibler Distance (KLD) methods. Among the empirical models, IRI Plas TEC is generally present to be better results than other models for all storm processes. It can be stated that IRI 2016 is better in the storm return phase compared to other phases of the storm.

Atmospheric Density Response to a Severe Magnetic Storm Detected by the 520 km Altitude Spherical Satellite

The polar-orbiting spherical experimental satellite of China for atmospheric density detection with an altitude of ~520 km was successfully launched on 14 October 2021. Based on the dynamic inversion method for atmospheric density and the precise orbit determination data obtained by its GNSS, we inverted the orbital atmospheric density during the severe geomagnetic storm in early November 2021. In this paper, we compared the atmospheric density data obtained by the spherical satellite with the simulations of the MSISE00 and the DTM, evaluated their error distribution, and analyzed the response of the atmospheric density during the severe geomagnetic storm in the dawn–dusk orbit of 520 km altitude. The properties and the physical processes for the atmospheric density of the time evolutions in different latitudes and the global distributions during the severe geomagnetic storm were obtained. We found that the substantial disturbance enhancement and recovery of the atmospheric density of the dawn–dusk orbit have a close correlation with the geomagnetic indexes Kp and Dst. The elevation extends from the poles to the equator, and the relative variation in two hemispheres demonstrates a bimodal nearly symmetric growth structure. The maximum relative variation of the two hemispheres both occurred in the middle latitude, and, for this case, the enhancement of atmospheric density in the mid-latitude region accounted for a larger proportion. The asymmetry between the northern and southern hemispheres is demonstrated by the fact that the absolute value and absolute change in the southern hemisphere in summer are larger than those in the northern hemisphere, and the bimodal structure of the relative variation is inclined to the northern hemisphere.

Solar Energetic-Particle Ground-Level Enhancements and the Solar Cycle

Severe geomagnetic storms appear to be ordered by the solar cycle in a number of ways. They occur more frequently close to solar maximum and the declining phase, are more common in larger solar cycles, and show different patterns of occurrence in odd- and even-numbered solar cycles. Our knowledge of the most extreme space-weather events, however, comes from spikes in cosmogenic-isotope (14C, 10Be, and 36Cl) records that are attributed to significantly larger solar energetic-particle (SEP) events than have been observed during the space age. Despite both storms and SEPs being driven by solar-eruptive phenomena, the event-by-event correspondence between extreme storms and extreme SEPs is low. Thus, it should not be assumed a priori that the solar-cycle patterns found for storms also hold for SEPs and the cosmogenic-isotope events. In this study, we investigate the solar-cycle trends in the timing and magnitude of the 67 SEP ground-level enhancements (GLEs) recorded by neutron monitors since the mid-1950s. Using a number of models of GLE-occurrence probability, we show that GLEs are around a factor of four more likely around solar maximum than around solar minimum, and that they preferentially occur earlier in even-numbered solar cycles than in odd-numbered cycles. There are insufficient data to conclusively determine whether larger solar cycles produce more GLEs. Implications for putative space-weather events in the cosmogenic-isotope records are discussed. We find that GLEs tend to cluster within a few tens of days, likely due to particularly productive individual active regions, and with approximately 11-year separations, owing to the solar-cycle ordering. However, these timescales would not explain any cosmogenic-isotope spikes requiring multiple extreme SEP events over consecutive years.

ROTI‐Based Stochastic Model to Improve GNSS Precise Point Positioning Under Severe Geomagnetic Storm Activity

AbstractFor global navigation satellite system (GNSS), ionospheric disturbances caused by the geomagnetic storm can reduce the accuracy and reliability of precision point positioning (PPP). At present, common stochastic models in GNSS PPP, such as the elevation angle stochastic (EAS) model or carrier‐to‐noise power‐density ratio () based SIGMA‐ model, do not properly consider storm effects on GNSS measurements. To mitigate severe storm effects on GNSS PPP, this study further implements the rate of total electron content index (ROTI) parameter into the EAS model referred to as the EAS‐ROTI model. This model contains two operations. The first one is to adjust variance of GNSS measurements using ROTI observations on EAS model. The second one is to determine the ratio of the priori variance factor between pseudorange and carrier phase measurements during severe storm conditions. The performance of EAS‐ROTI model is verified by using a large number of international GNSS service stations datasets on 17 March and 23 June in 2015. Experimental results indicate that on a global scale, the EAS‐ROTI model improves the PPP accuracy in 3D direction by approximately 12.9%–14.7% compared with the EAS model, and by about 24.8%–45.9% compared with the SIGMA‐ model.